JPH0761434B2 - Material permeable membrane - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for forming a polymer thin film on a solid surface by using a plasma polymerization reaction method, and in particular, a fluorine-containing organic compound and a sulfur compound as raw material components. By doing so, an ionic functional group of —SO ₃ ^— can be provided in the film, and a material useful for various applications including electronic materials is provided.

[Prior Art] A method of forming a thin film of a fluorine-containing compound by a plasma polymerization method using a fluorine-containing organic compound is known, and modification of a substrate surface, that is, chemical resistance, water / oil repellency, abrasion resistance,
Many studies have been conducted aiming at many features such as heat resistance and insulation. Among them, regarding the plasma polymerized film in the two-component system of the fluorine-containing organic compound and other chemical substances,
Combination of perfluoro compound and ammonia
61-97008), a combination of a fluorine-containing organic compound and a silicon-containing compound (JP-A-60-255111, JP-A-60-2615).
No. 28) is known. On the other hand, the method for chemically synthesizing an ionic fluorine-containing polymer is as disclosed in Takaomi Satokawa: Functional fluorine-containing polymer, Nikkan Kogyo Shimbun, P11, etc.

[Problems to be Solved by the Invention] However, there is no known method for forming a thin film of a fluorinated compound containing an ionic functional group, and by using the present invention, surface modification of various base materials can be efficiently performed. Therefore, it can be applied to a substance permeable film, an electronic material, a medical material and the like.

[Means for Solving the Problems] The present inventors provide a mixed gas composed of a fluorine-containing organic compound and a sulfur compound for a plasma polymerization reaction,
The present invention has been completed by succeeding in efficiently introducing an ionic functional group composed of —SO ₃ H or —SO ₃ F into a film. That is, the present invention is formed by subjecting a fluorine-containing organic compound and a sulfur compound to a plasma polymerization reaction to form on a substrate, an ion comprising a polymer thin film having a —SO ₃ — structure in the molecule. It is a substance-permeable membrane having exchangeability.

The fluorine-containing organic compound that can be used in the present invention is not particularly limited, but it is preferable that the compound has a large fluorine content. Further, an unsaturated compound which is a perfluoro compound and is highly reactive is more preferable. That is, perfluorobenzene and its derivatives, or fluorofluoroolefins such as tetrafluoroethylene, trifluoroethylene, vinylidene fluoride, and chlorotrifluoroethylene, or hexafluoropropene, hexafluoroacetone, or fluoroalkyl acrylate esters and Methacrylic acid esters, fluorovinyl esters or other perfluoro compounds and fluorine-containing organic compounds can be used. The ionic compound that can be used in the present invention is preferably a sulfur oxide such as SO ₂ or SO ₃ , but H ₂ S, SF ₆ and other sulfur compounds can also be used as long as they are in the presence of an oxygen compound.

As the mixing ratio of the fluorine-containing organic compound and the sulfur compound,
It is sufficient that the sulfur compound is 5% by weight or more based on the whole. If the sulfur compound content is 5% by weight or less, the amount of ionic functional groups in the film is small and a sufficient effect cannot be obtained. In particular, when considering the high ionization rate in the film, the sulfur compounds account for 20% of the total.
It is preferably at least wt%.

The raw material compound of the present invention as described above has various modes such as gas, liquid, and solid at room temperature and atmospheric pressure. However, liquid or solid is used under reduced pressure and, if necessary, vaporized by heating. It The supply amount of the raw material compound to the plasma polymerization reaction system is not particularly limited, but is 0.5 to 200 cm ³ (S
TP) / min.

The discharge method used for generating plasma is not particularly limited, and a commonly used method can be used. That is, plasma generation is carried out by a reaction device of either an internal electrode type or an electrodeless type utilizing direct current discharge, low frequency discharge, high frequency discharge, microwave discharge, or the like.

The shapes of the electrodes and coils at this time, and the structures of the cavity and the antenna in the case of microwave discharge are not particularly limited, and a generally used plasma reactor is used.

The plasma electron temperature in the plasma reaction zone in the present invention is 5,000 to 80,000 K, preferably 6,000 to 5
It is 0,000K. Plasma electron temperature is less than 5,000K, or
Above 80,000K, there is a drawback that the reaction efficiency is significantly reduced. The plasma electron temperature in the above range can be set by the feed rate of the raw material to the reaction system and the vacuum degree of the reaction system.

The raw material gas may be supplied to the reactor only by the raw material gas, but an inert gas such as helium or argon or a fluorine-containing gas such as CF ₄ may be used as the carrier gas. The vacuum degree of the system in this case is 1 × 10 ⁻³ to 10
It is preferable to adjust to the range of 0 Torr.

The substrate that can be used in the case of carrying out the plasma polymerization reaction of the present invention is not particularly limited, and may be a smooth or porous material such as glass, quartz, metal, semiconductor, ceramic or plastic. The shape of the base material can be various shapes such as a plate shape, a spherical shape, and a cylindrical shape.
There is no particular limitation. These substrates may be cooled or heated, and are preferably subjected to the reaction at about 0 ° C to 200 ° C. Above 200 ° C, there is a drawback that the production rate of the plasma polymerized film becomes slow. The production rate of the plasma polymerized film is 0.5 to 20Å / s.

The film thickness of the plasma-polymerized film produced by the present invention can be adjusted by the supply amount of the source gas, the degree of vacuum, the reaction time, etc., and the film has good surface properties and is uniform and free of defects in the range of 10Å-10 μm Can be obtained.

The plasma polymerized film obtained as described above contains --SO in the film.
₃ ^- of which it has an ionic functional group. This is, after ammonia (NH ₃₎ were reacted in the generation layer, by measuring the infrared absorption ^{_{spectrum, -SO 3 - NH 4 + (}} 1120cm -1,
It can be confirmed by the presence or absence of vibration of 1400 cm ^-1 ). Further, it can be seen that the plasma-polymerized film of the present invention is soluble in an organic solvent having high polarity, and the crosslinking reaction does not proceed in the film. Furthermore, in the plasma polymerized film in the system of the perfluorobenzene derivative and the sulfur oxide, the unsaturated double bond remains in the film. The above points are truly surprising in comparison with the point that the unsaturated double bond does not remain in the film and the crosslinking reaction is promoted in the case of the plasma polymerized film containing only perfluorobenzene.

Further, the plasma polymerized film of the present invention has high surface hardness and high adhesion to the substrate. Further, it has low surface energy, low refractive index, heat resistance, weather resistance, chemical resistance, etc., which are features of the fluorine-containing compound. Hereinafter, the present invention will be described with reference to examples, but the invention is not limited thereto.

Examples 1 to 3 The induction electrodeless discharge type plasma polymerization reactor shown in FIG. 1 was used.

The reaction tube 1 was evacuated by the exhaust pumps 6 and 7 to 1 × 10
After reducing the pressure to ^-4 Torr or less, etching was performed with argon plasma (rf discharge power 25 W) for 10 minutes to remove the adsorbed water in the system. The pressure inside the system was reduced to 1 × 10 ^-4 Torr again and the total flow rate was adjusted to 4.0 cm ³ (ST
The source gas was introduced so that P) / min. At this time, high-frequency oscillator (SKN-05P manufactured by Japan High-frequency Co., Ltd.); 13.56MH
Using Z, 100 W of discharge energy was introduced into the system by the external coil 3 to carry out plasma polymerization reaction.

As a raw material gas, perfluorobenzene and SO ₂ gas were used, and the mixture composition had a molar ratio of 3/1 (Example 1), 1/1 (Example 2), 1 /
3 (Example 3). A uniform, yellow transparent film was formed on the glass plate 2 regardless of the composition of the raw materials. The film thickness, surface hardness, surface energy, and total ion exchange capacity of the obtained film were measured. The results are shown in Table 1. The film thickness is measured with a stylus pressure type film thickness meter, and the surface hardness is JIS K54.
The pencil hardness was evaluated according to 00. Further, the total ion exchange capacity was calculated from the pH change by immersing in a KCl solution for 10 days.

Example 4 The plasma-polymerized films produced in Examples 1 to 3 were peeled off from the glass substrate, and the infrared absorption spectrum was measured by FT / IR-3 manufactured by JASCO Corporation by the KBr tablet method. Results are shown in FIG. According to this, the raw material gas charge ratio is 3 /
It can be seen that there is no significant difference in the products under the three conditions of 1, 1/1 and 1/3.

Further, the absorption of the benzene ring to 1500 cm ^-1, S = 0 to 1180 cm ^-1
The expansion and contraction vibrations of are respectively confirmed.

[Advantages of the Invention] According to the present invention, a fluorine-containing polymer thin film containing an ionic functional group can be easily obtained, and the surface of various substrates is improved to have excellent physical properties such as water / oil repellency and lubricity. Therefore, it is useful as a substance permeable film, an electronic material, a medical material and the like.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a plasma polymerization reactor for carrying out the present invention, and FIG. 2 shows an infrared absorption spectrum of a thin film obtained by the present invention. DESCRIPTION OF SYMBOLS 1 ... Reaction tube, 2 ... Base material 3 ... External coil, 4, 8 ... Needle valve 5 ... Cooling trap, 6 ... Diffusion pump 7 ... Rotary pump, 9 ... Raw material gas 10 ... Vacuum gauge

Claims (1)

[Claims] 1. An ion comprising a polymer thin film having a —SO ₃ — structure in a molecule formed on a substrate by subjecting a fluorine-containing organic compound and a sulfur compound to a plasma polymerization reaction. An exchangeable substance permeable membrane.